Everglades photo: Everglades National Park

This wide, shallow river, North America's only flooded savanna, wasn't like other rivers: it had no current, no falls or rapids, no sound. Beginning at an elevation of less than 20 feet, its waters, at depths from a few inches to perhaps two feet, flowed southward along the subtle slope of the land at the imperceptible rate of 100 feet a day, taking years to meet the open waters of Florida Bay 100 miles away. During their journey, these waters passed through pond apple swamps, sawgrass prairies, and mangrove islands - each habitat with its own distinct set of plants and animals.

During the dry season, the waters of the Everglades became concentrated in central marshes known as sloughs, the deepest part of the ecosystem. This process also concentrated prey species, which provided needed food to wading birds and a wide assortment of other animals. Diverse habitat types, varying water depths and abundant food all helped create the Everglades' extraordinary richness of life.

Throughout the first half of the nineteenth century, South Florida remained a single, huge ecosystem - one of the richest, densest, most intricate the world has ever seen - connected from end to end by perhaps the most efficient water delivery and treatment system nature ever devised. Boundless indeed it must have seemed to the settlers pouring in from neighboring states at mid-century. Boundless and, because this was the age of expansion, worthless - or so Florida's first legislature declared, while appealing to Congress for help in draining it.

Swampy, mosquito-infested, impenetrable, the Everglades epitomized "wasteland" to the nineteenth century settlers. The state parceled out the land cheaply to people willing to drain it. Entrepreneurs built canals, railroads and hotels along the East Coast. In 1905, Governor Napoleon Bonaparte Broward promised to drain the Everglades once and for all and build an "empire" in its place. The state encouraged the introduction of exotic plants, like the aggressive melaleuca from Australia, to suck water out of the marshes and, over the course of the next two decades, proceeded to cut a 440-mile network of locks, dams, levees and canals deep into the wetlands. Farming boomed on the newly reclaimed fertile muck soil, Florida's version of "black gold."

When a massive hurricane hit in 1928, earthen levees gave way, drowning some 2000 people and prompting the U.S. Army Corps of Engineers to construct a dike that eventually encircled Lake Okeechobee. But now, instead of too much water, there was suddenly too little. In the 1930s, when the great drought made a Dust Bowl of the plains, Florida went dry too. To their dismay, farmers found that their uniquely rich organic soils burned like tinder, and smoke filled their air for miles. Soils, dried to powder, blew away.

Then in 1947 the rains returned, and hurricanes left most of southeastern Florida under water, which stood in places for half a year. The Army Corps was called in again. By the time their massive flood control project was complete in the 1970s, the Kissimmee River had been transformed into a 300-foot-wide canal half its original length, 1,350 square miles of wetlands had been turned into shallow reservoirs or impoundments, and 1,400 miles of canals and levees had been carved into the Everglades. Called the Central and Southern Florida Project, few engineering projects in the history of the world can match it for sheer scale and ambitions. For unintended consequences, perhaps none can.

When the project was designed, the population of South Florida stood at about 500,000, with fewer than 20,000 living in the fragile Keys. Today more than 80,000 call the Keys home, and south Florida's 8 million year-round residents are joined by more than 12 million tourists annually. By 2050, planners anticipate, south Florida's total population will more than double. Human demands for water, both for agriculture and urban uses, are growing rapidly.

Now half of its original size and cross-crossed by the Corps' elaborate network of water-diverting structures, the remaining Everglades no longer receives the historic slow and steady sheet-flow of water from Lake Okeechobee. Seventy percent of the natural flow has been diverted to estuaries on the Gulf and Atlantic Coasts, where, laden with agricultural pollution, it disrupts the health of these valuable habitats. As for the water that is released through the Everglades, its timing and distribution no longer correspond to the needs of the plants and animals that depend on it. Water quality has also deteriorated. Heavy loads of phosphorus, nitrogen and mercury enter the system from agricultural and urban sources. The result: signs of ecosystem stress are everywhere.